VI EM SS 0Il CONTl 0LS EXllAUST SYSTEMS 4A 35 8 If greater than specified turn screw s clock I II IIIlM I lIIItIIl wise until specified CO reading is obtained 9 Allow ten seconds for meter to stabilize after Six cylinder vehicles without the throttle stop each adjustment solenoid are equipped with a dashpot assembly For required adjustment refer to Section NOTE If the idle speed changed more than 30 rpm 4 Fuel Carburetion during the mixture adjustment reset to the specified mm and repeat the adjustment until the speclried car d e d mum momma not vnu Chnkt I lnk g An often overlooked but highly important emission related component is the exhaust manifold heat valve All choke linkage including the fast idle cam should This valve can affect the gas mileage performance be checked for free movement at the mileage intervals driveability and especially emission levels specified in the Mechanical Maintenance Schedule This valve is to be inspected for correct operation Free carburetor linkage by applying Jeep Car and lubricated with Jeep Heat Valve Lubricant or buretor and Combustion Area Cleaner or equivalent equivalent every 5000 miles on Cherokee Wagoneer Never use oil to lubricate carburetor linkage and Truck models and every 30 000 miles on CJ For correct choke system adjustments refer to models Refer to the Exhaust section for service proce Fuel Carburetion section of this manual dures EXHAUST SYSTEMS rm P nmm was Erma mamma nan vnu M 35 GEIIEIIAL gine warmup The valve is closed directing exhaust heat to the intake manifold when the counterweight is The basic exhaust system on all vehicles consists of in the extreme counterclockwise position when viewed a front exhaust pipe muffler and tailpipe Refer to from the counterweight end fig 4A 46 As the engine figures 4A 40 4A 41 4A 42 and 4A 43 for exhaust reaches operating temperature the thermostatic system components spring heats up and loses tension allowing counter All CJ models with V 8 engines are equipped with a weight to open the valve fig 4A 47 catalytic converter The manifold heat valve must operate freely and The exhaust system must be properly aligned to should be checked and lubricated every 5 000 miles on prevent stress leakage and grounding If the system Cherokee Wagoneer and Truck models and every grounds on any body panel it may amplify objec 30 000 miles on CJ models with Jeep Heat Valve tionable noises originating from the engine or the Lubricant orequivalent body When inspecting an exhaust system check for cracked or loose joints stripped bolt threads and cor rosion damage Replace all parts that are badly cor n Yl roded or damaged do not attempt to repair 1 Remove and separate intake and exhaust manifolds refer to Section 1A Six Cylinder Engine 2 Remove manifold heat valve assembly by cutt EX A MA F0 D MEAT VALVE ing heat valve shaft on both sides of valve 3 Lift valve from manifold and drive out remain x cy dgr Mlm ing shaft sections and bushings 4 Install new bushings using heat valve shaft as A thermostatically controlled heat valve in the ex aguide pin haust manifold directs exhaust heat to the floor of the 5 Ream out new bushings with a 5 16 inch drill intake manifold for rapid fuel vaporization during en bit to remove all burrs